Bell metal is an alloy of

Match List-$I$ with List-$II$ and select the correct code.

List-$I$	List-$II$
$I.$ Cyanide process	$a.$ Ultrapure $Ge$
$II.$ Froth floatation process	$b.$ Pine oil
$III.$ Electrolytic reduction	$c.$ Extraction of $Al$
$IV.$ Zone refining	$d.$ Extraction of $Au$

Read the following statements :
$(I)$ $Al$ has greater affinity than that of $Cr$ for oxygen
$(II)$ $Al$ can be used for reduction of $Fe_2O_3$
$(III)$ Carbon is used for reduction of $PbO$
$(IV)$ $SnO_2$ can be reduced by carbon
Choose the correct set of statement$(s)$:

What are the metals and their approximate percentages in German silver?

List-$I$ shows reactions involved in the metallurgy of $Pb$ (lead) and List-$II$ shows the names of the processes. Match List-$I$ with List-$II$ and select the correct code for your answer.

List-$I$	List-$II$
$(P) \ PbS + 2PbO \xrightarrow{\Delta} 3Pb + SO_2 \uparrow$	$(1) \ \text{Smelting}$
$(Q) \ PbS + \frac{3}{2}O_2 \xrightarrow{\Delta} PbO + SO_2 \uparrow$	$(2) \ \text{Self reduction}$
$(R) \ PbCO_3 \xrightarrow{\Delta} PbO + CO_2 \uparrow$	$(3) \ \text{Calcination}$
$(S) \ PbO + C \xrightarrow{\Delta} Pb + CO \uparrow$	$(4) \ \text{Roasting}$

Flux is used to remove ...... .